The present invention relates to a vessel for sealingly storing therein liquid such as juices, liquors and the like, and more particularly, to a vessel simple in construction and mainly made of a laminated sheet material having at least a thermally bonding synthetic resin layer.
A vessel of the type described above is generally formed in the rectangular form so as to improve the transportability and efficiency of stock space by bending the sheet at right angle and thermally bonding the overlapping portions thereof so as to form the seam for constructing the vessel. Such a seam must possess a high hermetical sealing property with a high reliability while a high efficiency of production is required in order to protect the contents and lower the production cost. Further, in case the content of the vessel is to be successively consumed repeatedly, the hermetical sealing of the vessel must be insured repeatedly.
A vessel of the type described above was disclosed in Japanese Utility Model Public Disclosure No. 57-55718 (1982). The vessel disclosed therein comprises a cylindrical trunk member of rectangular cross section having two opposite open ends made of a laminated sheet material having on the inner surface thereof a thermally bonding synthetic resin layer and formed by outwardly bending the opposing side edge of the sheet material so as to be thermally bonded to each other for forming the cylindrical form of the trunk member, and two end members each having an axially extending flange portion adapted to be fitted in the respective open end of the trunk member, the flange portion of each end member being provided on the outer surface thereof with a thermally bonding synthetic resin layer so as to be thermally bonded to the respective open end of the trunk member when the former is fitted in the latter and heated for effecting the thermal bonding therebetween. Since a clearance is necessarily formed between the seam of the trunk member and the opposing corner of the end member, an outwardly projecting thin ear portion is formed at the opposing corner of the end member by the medium of the thermally bonding synthetic resin layer provided on the outer surface thereof in order to seal the clearance. The ear portion is deformed and fills the clearance for achieving the hermetical sealing when the flange portion is fitted in the open end with the ear portion positioned in opposing relation to the seam of the trunk member and heated for effecting the thermal bonding therebetween.
With such a construction of the vessel described above, however, the orientation of the end member with respect to the orientation of the seam of the trunk member is strictly required in the automatic assembling line in the production of such vessels thereby considerably deteriorating the efficiency of the production of the vessels.
On the other hand, the present inventors have found out that a clearance tends to occur between the corner of the flange portion of the end member and the opposing corner of the open end of the trunk member even though no seam is formed there and such a clearance must also be sealed positively.